Searching for Axions and the String Axiverse in the Cosmo

by Dr Luca Visinelli (Stockholm University)

Tuesday 23 Oct 2018, 15:00 → 16:00 Europe/Rome

Aula Teorici (DIFA)

The low-energy limit of several string theories feature what is known as the “axiverse”, a plethora of light axions with masses spanning various orders of magnitude. I will first discuss astrophysical and cosmological constraints on axions at either end of this spectrum, using data from the cosmic microwave background anisotropies and from the gravitational microlensing. I then show how to assess the string parameters using a series of Bayesian analyses that take into account current limits on the tensor-to-scalar ratio and the primordial isocurvature fraction. Based on hep-ph/1809.06382.